On this year’s Geneva Motor Show, a 911 GT3 R Hybrid will make it debut, exactly 110 years after Ferdinand Porsche developed the world’s first car with hybrid drive, the Lohner Porsche Semper Vivus.

110 years later, Porsche goes racing again with a car driven by electric power on the front wheels...

The innovative hybrid technology featured in the car has been developed especially for racing, differing fundamentally in its configuration and components from conventional hybrid systems. In this case, front the front wheels are driven by two electric motors developing 60 kW each, supplementing the 480-bhp four-litre flat-six at the rear of the 911 GT3 R Hybrid.

Instead of the usual batteries in a hybrid road car, an electrical flywheel power generator fitted in the interior next to the driver delivers here the electric energy to the two front electric motors.

The flywheel generator is itself an electric motor which has its rotor spinning at speeds of up to 40,000 rpm, in effect storing energy mechanically as rotation energy.

This flywheel generator is charged whenever the driver applies the brakes, by electric current coming from the two electric motors in the front axle. These reverse their function and act themselves as generators under braking. The flywheel generator sets its rotor spinning ever higher by using this electric current delivered by the front motors.  

Whenever the driver wants to use the electric power from the charged flywheel generator, for example when accelerating out of a bend or when overtaking, the flywheel is being slowed down electromechanically in the generator mode and supplies herewith up to 120 kW to the two electric motors at the front from its kinetic energy. This additional power is available to the driver after each charging process (by fully braking at racing speeds) for approximately 6 - 8 seconds.

The Porsche “flywheel” hybrid transforms the energy, which was hitherto converted into heat upon every application of the brakes, cleverly into additional power.

After its debut in Geneva the 911 GT3 R Hybrid will be tested in long-distance races on the Nürburgring. The highlight of this test programme will be the 24 Hours on the Nordschleife of Nürburgring on 15/16 May. The focus is not on the 911 GT3 R Hybrid winning the race, but rather serving as a spearhead in technology and a “racing lab” providing know-how on the subsequent use of hybrid technology in road-going sports cars. We will follow up closely the development of this clever racing Porsche on this site!

Hans Knol ten Bensel